Abstract: Spraying litchi with 0.03% and 0.05% chitosan a month before harvest, the results showed that the rots of postharvest litchi were controlled effectively, perhaps mainly due to the accumulations of chitinase and β-1,3-gluconase in litchi pericarp, more content of organic acids in litchi aril and slowing down the activities of both of enzymes mentioned above and the concentration of organic acids. It also appeared that the 0.05% chitosan is more effective than 0.03%.

Key words: litchi, preharvest spraying, chitosan, postharvest rot